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WorksheetsWind Tunnel Technology
Total questions: 60
Worksheet time: 1hrs 15mins
Where was the first closed circuit wind tunnel built?
Salzberg
Gottingen
Milan
Who built the first wind tunnel?
Brunel
Gustav Eiffel
Stephenson
Why do most car racing teams use closed loop wind tunnels?
Why do closed loop wind tunnels need to be cooled?
Why is the fan mechanically isolated from the ground and the structure of the tunnel by a seismic mass?
What fluid dynamic problems do fans introduce into the air flow?
Why are static vanes placed downstream of the fan?
What is the maximum air velocity in the Sauber wind tunnel
288km/hr
540m/s
80 m/s
Why does the cross section of the wind tunnel expand progressively after the fan, until it reaches the contraction just before the test section?
It maintains the working area of the tunnel by compensating for the build up in boundary layer.
It reduces the friction losses between the air and the wall of the wind tunnel.
What are the disadvantages of a closed loop wind tunnel?
High cost of construction.
More difficult to operate and maintain than an open loop tunnel.
Takes up greater space than an open loop tunnel.
Aerodynamic Friction forces increase with?
The cube of the velocity.
The square of the velocity.
What happens to the air velocity as it travels around the tunnel?
It increases greatly.
It increases slightly.
It reduces slightly.
What happens to the 3 megawatts of power which is needed to drive the wind tunnel fan?
What is the maximum flow rate of the Sauber wind tunnel?
1200 cubic metres per second
120000 litres per second
How much thrust does the Sauber wind tunnel fan produce
49050 Newtons
5000 Newtons
What are the advantages of an Open Circuit Wind Tunnel
Low Cost to build.
Low running costs
What type of heat exchanger is used to maintain the temperature of the air in the wind Tunnel?
An oil cooled heat exchanger.
Heat is dissipated through the walls of the tunnel.
A water cooled heat exchanger.
An air cooled heat exchanger.
Why are vanes used in the right angle bends of the wind tunnel?
To minimize the aerodynamic losses in the bends.
To maintain the flow direction of the air.
To help reduce the vorticity/swirling of the air.
What two shapes are the turning vanes?
Curved.
Aerofoil.
Hexagonal.
Hemispherical
What two effects does the contraction have on the air?
Reduces the velocity of the air.
Increases the air pressure.
Reduces the size of vortices in the air.
Increases the velocity of the air.
Identify the components which help to reduce the vorticity of the air.
Vanes.
Honeycomb screen.
Fine wire meshes.
Heat exchanger Matrix.
All of the above
What type of working section do Sauber use most of the time?
Open Jet.
Closed jet.
Slotted wall.
Three quarter open jet.
What type of test section is normally used for acoustic testing of vehicles?
The walls of the test section cause the air velocity around the model to increase above that found in racing conditions.
True
False
3/4 open jet wind tunnels simulate most effectively the conditions found on the race track.
false
True
Contoured test sections provide a method of testing in undersized wind tunnels.
True
False
Adaptive wall technology is a method of testing different shaped models in a smaller wind tunnel.
False
True
Motor sport wind tunnel technology is largely an adaption of aerospace wind tunnel technology.
False
True
There is a boundary layer on the road surface beneath the racing car.
True
False
The boundary layer in the Sauber wind tunnel is typically what thickness?
80 to 90 mm
40 to 50 mm
5 to 10 mm
Give two methods which are used to remove the boundary layer in front of the test section.
What velocity does the moving ground plane operate at?
The test section air speed.
The simulated race car velocity.
3/4 of the race car velocity.
The boundary layer continues to grow on the moving ground plane.
True
False
Ground plane technology has been used to simulate the take-off and landing of aircraft.
True
False
Which method of mounting the model race car in the wind tunnel gives the least overall aerodynamic interference?
Model mounting.
Wheel mount arms
Sting
Overhead wire suspension.
Overhead mounting at the center of the model
What is the name of the model movement system which Sauber uses?
Model movement.
Tripod
Septapod
Hexapod
How would you describe the movement of the model race car in the Sauber wind tunnel.
Model movement.
The model moves smoothly
The model model moves quickly and stops to allow for data collection.
What effect may the wheels of the model have on the data collected during testing?
Why Is so much emphasis being put on the aerodynamics of the wheel?
Because it changes the air flow around the car
It increases the drag on the car
How many sets of tyres are supplied to the race teams for wind tunnel testing?
Tyres
10 sets
5 sets
12 sets
What type of moving ground plane system is used by Sauber?
Moving ground plane.
Cooled Fabric Belt
Steel belt, air bearing
The moving belt ground plane system uses vacuum pumps to remove unwanted air from the air bearings
True
False
The moving Ground plane system must be able to support the following
Ground plane loading.
The weight of the car.
The aerodynamic downforce.
The weight of the car and the aerodynamic downforce.
What is the typical percentage repeatability of a load cell?
Load cells
0.1% at full scale load
0.02% at full scale load
1.5% at full scale load
How many load cells are normally used to gather information on a race car?
6
11
8
Which forces are being measured on the race car, using the load cells?
Force measurement.
Drag
Downforce
Side force
Smoke wands are commonly used in aerodynamic research?
True
False
How is the air pressure on the surface of the Car measured?
Lasers can be used to illuminate small particles moving over the model and measure their velocity and direction.
True
False
Scale model testing is less expensive than track testing.
True
False
A 60% scale model uses what percentage material volume to construct?
45%
21.6%
How do we calculate the forces on a full size car from measurements obtained from the model?
Multiply by the square of the difference in scale
Divide by the square of the difference in scale
Scale using the Drag Coefficient
What two other technique are used to develop race cars , besides the wind tunnel?
When testing a F1 race car model for the first time in the wind tunnel, why is the wind turned off?
Describe the the boundary layer flow condition over the race car which generates the highest down force.
Why did Mercedes use a smooth belt, when testing their 2022 Model and what effect did this have?
What technique is commonly used to visualize and measure the air flow around the model in the wind tunnel?
The 2022 Mercedes F1 race car suffered from porpoising, what is this and how does it occur?
How does a F1 race car generate a boundary layer under car, when the air is initially stationary?
Why is it important that the surface roughness of the rolling road matches the track conditions?
